In the existing display technologies, a display device must have the characteristic of a wide viewing angle when displaying a picture, and thus multiple users can view the same display device at the same time. However, the characteristic of a wide viewing angle of the display device may sometimes result in leaking the users' privacy. Therefore, some existing display products require a peep-proof function.
In the current touch display technologies, there is also a tendency to integrate a touch system and a display system into one device, for example, an in-cell touch display panel, to provide both touch control and display functions by means of carrying out touch sensing and updating display frames in a time-sharing manner. To achieve the peep-proof function, however, when the in-cell touch display panel is in the display mode, the display frame has the characteristic of a narrow viewing angle through voltage control. When the touch display panel is in the touch mode, a common electrode in the touch display panel is provided with a voltage or signal required for touch sensing. The voltage or signal provided to the common electrode in turn affects the arrangement of the display medium in the display panel, making the display frame unable to maintain the characteristic of a narrow viewing angle. Further, the electric field effect produced by the common electrode may also cause non-uniformity of the display frame.